late 2013 Mac Pro freezes constantly - GPU Hang

I've been having a very consistently recurring problem with my brand new Mac Pro freezing. I am unable to predictably reproduce the problem, unfortunately, which makes it hard to solve or troubleshot from the get go. Basically every time I boot up I get a full freeze of the machine anywhere from within the first 10 minutes to an hour of boot up... somewhere in that window usually. Whatever applications are open will freeze, including system OS and usually only the mouse will be able to move but I will not be able to click on anything or Force Quit or restart. My only option is to hard reboot by holding down the power button for several seconds.

It doesn't seem to be isolated to occurring with any one application being open. I use my computer primarily for audio recording and editing. I use Avid Pro Tools HD 11.2. It's a version of their software supported to run on Mavericks 10.9.3 which is what I am running. I use it with their HD Native Thunderbolt hardware. Other than a few drivers installed to run audio and MIDI interfaces connected to the machine, I don't have much else installed on the computer yet. I do have a few 3rd party audio plugins installed, however, these problems were occurring before I installed much of anything on the machine.

I've checked Console each time I have the freeze ups and scroll to the log at the time it occurred. Almost every time without fail I get basically the following message in the Console log:

7/7/14 7:40:24.000 PM kernel[0]: [6:0:0] GPU HangState 0x00000000, HangFlags 0x00000004: IndividualEngineHang 0, NonEngineBlockHang 0, FenceNotRetired 1, PerEngineReset 0, FullAsicReset 1

7/7/14 7:40:24.000 PM kernel[0]: ** GPU ASIC Log Start **

7/7/14 7:40:24.000 PM kernel[0]: : 0x00006810 : 0x000000e3 : 0x00000001 : 0x00000018 : 0x0000a060 : 0x00000001 : 0x00000001 : 0x00006810

7/7/14 7:40:24.000 PM kernel[0]: : 0x00000001 : 0x00000015 : 0x00000000 : 0x00000001 : 0x00000047 : 0x00005009 : 0x00000001 : 0x00000058

.... a whole bunch of kernel panic spew, and then...

7/7/14 7:40:25.000 PM kernel[0]: ** GPU ASIC Log End **

7/7/14 7:40:25.000 PM kernel[0]: 0x000001f5 : 0x00000000 : 0x00000000 : 0x00000000

7/7/14 7:40:25.000 PM kernel[0]: : 0x00000000 : 0xc0036900 : 0x00000204 : 0x00000000 : 0x00080244 : 0x0000043f : 0xc0016900 : 0x00000208

... more spew logs, and then finally...

7/7/14 7:40:25.000 PM kernel[0]: : ** GPU Debug Info End **

7/7/14 7:40:25.000 PM kernel[0]: ------------------------

7/7/14 7:40:25.000 PM kernel[0]: GPURestartReportEnd

7/7/14 7:40:25.000 PM kernel[0]: Trying restart GPU ...

It's almost always saying something about a "GPU Hang" at the time of freeze up. I don't know much about what the possible problem could be but some initial research led me to believe it was graphics card related. I thought that because I was running two monitors perhaps the connections there were fouling up somehow. I am running two identical monitors simultaneously. One runs off a regular HDMI cable. The other was via a 3rd party Mini DisplayPort to DVI adapter. I thought perhaps the non-Apple branded adapter I was using could be the culprit? The Apple Store (of course) agreed and sold me the Apple DVI to mini DisplayPort adapter. I swapped it out but it did not solve my issue. Still having the freezes. Sometimes after the freeze happens I'll also get a pop up warning that my external hard drive connected via USB was ejected improperly, even though I hadn't touched anything?? The whole thing goes haywire.

It's been doing this for a few months now. I've contacted Apple Care and spent an hour on the phone with them which resulted in making an appointment at a local Apple Store with a Genius. This was after they recommended that I reset both the SMC and the PRAM on the machine, neither of which solved the issue either. I took the machine in and they kept it for 48 hours to do a full stress test to see if they could determine the issue. No problems were found. They gave me the computer back and could not reproduce my problem.

The problem still exists. So that's why I'm writing on here, out of desperation because I have a brand new Mac Pro, under warranty, that is essentially useless. I have a follow up call into Apple Care to see what my next steps are but I haven't gotten a call back.

The only next steps I can imagine are to possibly update to Mavericks 10.9.4 to see if that might help even though Pro Tools is not yet supported by that OSX version yet. Or do a full clean re-install of OSX and all software on the computer (yikes!).

Or Apple needs to swap me a new machine. This is unacceptable.

Anyone else having this issue??

Here are specs on the machine:

Mac Pro (late 2013, 6.1)

Processor 3.5 GHz 6-Core Intel Xeon E5

Memory 32 GB 1867 MHz DDR3 ECC

Graphics AMD FirePro D300 2048 MB

Software OS X 10.9.3 (13D65)

Boot ROM Version: MP61.0116.B04

SMC Version (system): 2.20f18